Khus or Vetiver (Vetiveria zizaniodes (L.) Nash., syn. Chrysopogon zizaniodes (L.) Roberty; family Poacaeae), is a perennial, wildly growing aromatic plant occurring all across India in variable agro-climatic conditions. India is considered to be the center of origin of vetiver (Lavania UC (2008): Vetiver in India: historical perspective and prospective for development of specific genotypes for environmental or industrial application. In, Truong P (ed.) Proc First Indian National Vetiver Workshop: Vetiver system for environmental protection and natural disaster management, Cochin, India 21-23 Feb. 1988, pages 40-47. As such, a higher order of genetic diversity with respect to ecological/geographic adaptation, morphometric traits, reproductive behaviour and essential oil concentration and composition is found in the Indian subcontinent, followed by Indonesia (Lal RK (2000) Genetic variability and association analysis for yield and yield components in indigenous and exotic collections of vetiver (Vetiveria zizanioides (L.) Nash). Jour. Spices Aromatic Crops 9: 133-136.).
Roots of vetiver are the source of world famous “Khus oil” which has considerable value in essential oil industry. Indians were the first to recognize vetiver for its aromatic and medicinal uses, followed by its other cottage and environmental uses in India and elsewhere (Lavania UC (2003) Vetiver root oil, and its utilization. Pacific Rim Vetiver Network Technical Bulletin, No. 2003/1, 12 pages, Office of the Royal Development Projects Board, Bangkok, Thailand, Lavania UC, Lavania S and Vimala Y. 2004. Vetiver system ecotechnology for water quality improvement and environmental enhancement. Current Science 86:11-14, Lavania UC (2008). The total world production of khus oil is estimated to be 250-300 tonnes per year. In India, about 20-25 tonnes oil is produced annually, which is much below to meet even the indigenous demand of the oil for perfume, essence, attar and soap industries.
Two distinct morphological complexes of vetiver are found to inhabit spatially separated geographic regions in India: one in the north along the Indo-gangetic plains and adjoining areas mainly in the states of Rajasthan, Madhya Pradesh, Uttar Pradesh and Bihar, and the other in the south along the east and west coasts of Indian peninsula in the states of Andhra Pradesh, Karnataka, Tamilnadu and Kerala. The two races are distinctly different. The north Indian wild types represented by “Bharatpur type” are profuse flowering high seed-setting having narrow leaves with vigorous roots producing low concentration superior quality laevorotatory root oil (ruh-khus or khus oil) and the south Indian “cultivated type” that are late and low flowering with high pollen sterility and non seed-setting with wider leaves producing low quality dextrorotatory root oil (vetiver oil) resembling Java vetiver (see, Lavania 2008). Depending upon the oil quality and free vetiverols, there could be a price difference of four fold between laevorotatory and dextrorotatory oils. The former mainly available in north Indian vetiver is considered to be superior quality (Lavania 2003).
Systematic cultivation of vetiver has been in practice in south India, mainly in Kerala (Thiruvambadi, Neyatunkara), Andhra Pradesh (East Godavari and Kurnool), Tamilnadu (Mettupalayam, Nilgiri and Coimbatore) and in small areas of Karnataka state. However, the Khus cultivation for profitability has been driven by increasing demand of its essential oil. As such, cultivation of vetiver has also been taken up in the Indian states of Uttar Preadesh and Bihar. However, its long duration (18 months) and poor root yields, variable oil content and quality and Khusinol (a desirable oxygenated sesquiterpine likened to Khusimol for its vetiverol characteristics) content just up to 10%, have hindered its acceptance among the farmers and perfume industry.
Extensive breeding efforts have been undertaken at various research centre in India to develop/identify suitable clones to produce homogenous population and uniform quality for its essential oil under vetiver cultivation (for details see Lavania 2008 for an overview), but the problem of long gestation period for crop under cultivation and quality of root-essential oil has long bothered the scientists.
The present invention i.e. ‘CIMAP-KHUSINOLIKA’, overcomes this problem to a large extent by reducing the crop gestation period just to six months, and at the same time realizing desired quality of essential oil rich in Khusinol. This clone could yield more than 1% essential oil concentration containing 45-50% Khusinol just after 6 months of planting. As a super-short duration clone, this plant type provides opportunities to suitably accommodate vetiver cultivation into existing cropping systems. It is worth emphasizing that in literature, the highest Khusinol in Chrysopogon zizanoides is reported to be 19.15% (Kirici S, Inan M, Turk M and Giray E. S. 2011. To Study of Essential Oil and Agricultural Properties of Vetiver (Vetiveria Zizanioides) in the Southeastern of Mediterranean. Advances in Environmental Biology 5: 447-451.). But this clone ‘CIMAP-KHUSINOLIKA’ is distinct and unique from all the available clones, since it is endowed with highest amount of sesquiterpene “khusinol”, which is reported for the first time.
Khusinol is a sesquiterpene alcohol (with molecular weight 220), one among the group of 20 vetiverol sesquiterpene, found only in the essential oil of Vetiveria zizanoides contributes to pleasant aroma of vetiver oil along with khusimol and zizanol. Isolation of this sesquiterpenoid from a complex blend of vetiver essential oil is difficult. This is a cadinane-type compound (which usually used as wood protective probably due to some repellant properties) used as a starting material for the synthesis of compounds like khusinodiol. Additionally other compounds namely (+)-α-cadinol and iso-khusinol are also synthesized by using khusinol (Trivedi G K, Wagh A D, Paknikar S K, Chakravarthi K K, Bhatacharya S C, Terpenoids—LXXVI: Transformation products from BF3-catalysed reaction of khusinol. Tetrahedron, 1966, 22(5), 1641-1649). Hence high khusinol is desirable in the essential oil of vetiver.